Many clinical practices involve percutaneous insertion of needles for biopsy and drug delivery by placing the tip of the needle safely and accurately in a lesion, organ, or vessel. Examples of treatments requiring needle insertions include vaccinations, blood/fluid sampling, regional anesthesia, tissue biopsy, catheter insertion, cryogenic ablation, electrolytic ablation, brachytherapy, neurosurgery, deep brain stimulation, and various minimally invasive surgeries (MIS). Conventionally, these surgical operations are carried out by a surgeon holding the trocar needle in his hand with one end of the trocar resting on a patient's skin. The other end of the trocar is tilted numerous times to establish an accurate alignment between the trocar and the target area. The alignment of the trocar is usually determined with the help of a medical imaging system such as X-ray radiography, magnetic resonance imaging (MRI), medical ultrasonography or ultrasound, computed tomography (CT) and others. Once the accurate alignment is confirmed, the surgeon has to maintain the alignment of the trocar by steadying his hand. The trocar is subsequently pushed into the patient's body to reach the target area. Targeting accuracy is crucial because poor placement of the trocar during biopsies leads to false negatives. Inaccurate seed placement during brachytherapy destroys healthy tissues instead of cancerous tissues, sometimes with catastrophic outcomes.
An example of these surgical operations is percutaneous renal surgery. Percutaneous renal surgery is a minimally invasive procedure for establishing a keyhole access in percutaneous nephrolithotomy (PCNL) to remove a kidney stone. In this procedure, a trocar is passed through a patient's skin through the body layers into the kidney to reach a stone target. Surgical instruments such as guidewire, ultrasonic probes and vacuum are then passed through the hole in the trocar to carry out the stone removal process.
The duration of the trocar insertion procedure typically ranges from 10 minutes to 1.5 hours and throughout the procedure, the C-arm fluoroscope has to be in operation. Consequently, both the patient and surgical crew are subjected to long exposure of X-ray and this could be a potential health hazard in the long run. In addition, due to the elaborate procedure, there may be instances when the trocar has to be withdrawn and the entire procedure needs to be repeated. This may aggravate the condition of the patient as multiple punctures of the patient's body may increase the risks to the patient such as significant bleeding, hematoma formation and infection. The procedure may have to be called off and rescheduled, thus causing much distress to the patient and loss of precious time of the healthcare professionals.
To address the problems above, robotic arms are used to perform the trocar insertion procedure. For example, current approaches utilize robotic arm surgical systems which mimic the standard manual procedure. In other words, the systems are manually controlled by the surgeon, e.g. using a manipulator such as a joystick, to align the trocar with the target area. Also, these conventional systems are bulky and slow in processing. It is also expensive to manufacture the systems and implement the trocar insertion procedure using the systems.
Alternatively, the surgical procedures may be carried out using a robotic system that controls a flexible needle with steering capabilities in subsurface tissues under image feedback to reach a target in the patient's body. A variety of mechanisms may be used to steer the flexible needle, e.g. tip-based steering, lateral manipulation of the needle base and tissue manipulation as the needle is being inserted. Flexible needles can be used to steer around hard or sensitive tissues such as blood vessels and bones, allowing targets that are inaccessible by a straight-line path to be reached by the needles. Subsurface needle steering may also allow the trajectory of the needle to be manipulated, thus avoiding the need for repeating the whole surgical procedures. However, this technique is still time-consuming and requires iterative images to be obtained and processed.
A need therefore exists to provide a system for aligning a surgical tool that seeks to address at least some of the above problems.